1. Field of the Invention
The present invention relates generally to packaging and, more particularly, to packaging and methods for packaging for particulate and granular materials.
2. Description of Related Art
Particulate and granular materials are commonly packaged in bags, sacks or other packaging materials (collectively referred to herein as “bags”) constructed of paper. As used herein, the term “particulate materials” refers to powdery materials that generate dust when disturbed, such as during packaging. For purposes of example only and not limitation, particulate materials can include cementitious materials, such as cement and concrete mixes, limestone, fly ash, bottom ash, powdered sugar, etc. As used herein, the term “granular materials” refers to materials that are composed of granules or grains, or have a grainy texture, and which may or may not generate dust when disturbed. For purposes of example only and not limitation, granular materials can include sand, pea gravel, sugar, salt, etc.
The conventional paper bags used to package particulate and granular materials are generally closed at one end either when the bag is made or prior to filling by folding the sides of the bag inwardly in an overlapping configuration and then securing the sides together using an adhesive. The bags are filled with the particulate or granular material through the open end of the bag, which is then closed by folding the sides of the bag inwardly in an overlapping configuration and then securing the sides together using an adhesive.
Conventional paper bags are structured to allow air to escape from the interior of the bags so that the bags can be compressed when the bags are stacked, such as on a pallet. However, conventional paper bags have several disadvantages. For example, in addition to allowing air to escape, conventional paper bags also can allow fine particles from the particulate or granular material inside the bag to escape, which can result in appreciable amounts of dust, particularly when storing the bags in an enclosed space such as a warehouse or inside a store. Conventional paper bags also are susceptible to rupturing or tearing if not handled properly, which can result in product spillage and waste. Conventional paper bags also allow moisture to permeate the bag, which will typically have an adverse effect on the particulate or granular material inside the bag. For example, where the bag is used to package cementitious material, moisture can lead to curing of the cementitious material inside the bag thereby rendering the product useless. This can be particularly problematic when storing or handling the bags outside where the bags can be exposed to rain, condensation or other wet ambient conditions. Conventional paper bags also can be difficult to load and unload manually when the bags are filled with particulate or granular material. For example, bags used to package cementitious material are typically offered in 29 lb, 44 lb, 50 lb, 60 lb and 80 lb bags, which are heavy and can be difficulty to carry.
Accordingly, there remains a need for packaging for particulate and granular material generally and cementitious materials in particular. The packaging should be capable of being filled and sealed using an automated filling machine and should allow the particulate or granular material to be stored so as to minimize leakage, spillage and exposure to moisture. The packaging should also be stackable when filled with particulate or granular material, such as on a pallet, and should also facilitate manual loading and unloading of the filled packaging.